| Autor: |
Max L. Sweat, Richard B. Young, Melvin J. Bryson |
| Rok vydání: |
1970 |
| Předmět: |
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| Zdroj: |
Biochimica et Biophysica Acta (BBA) - General Subjects. 215:119-124 |
| ISSN: |
0304-4165 |
| DOI: |
10.1016/0304-4165(70)90394-6 |
| Popis: |
1. 1. Evidence derived both from spectrometric and incubation studies shows that microsomes prepared by contemporary methods of differential centrifugation exhibit appreciable mitochondrial-like activity. This is particularly demonstrable in incubation studies where the addition of the mitochondrial cytochrome P-450 reductase system (which is soluble and is extracted from the system by conventional produres) markedly increases II β-hydroxylation. The presence of significant quantities of mitochondrial-like cytochrome P-450 in microsomal preparations offers explanations for spectral responses to various steriod substrates observed in microsomal preparations. Induced difference spectra occur in these preparations both with II -deoxysteroid and 21-deoxysteroid substrates. 2. 2. The magnitude of spectral response induced by androstenedione in microsomal preparations is markedly different in comparison to that induced by II -deoxycorticosterone. Androstenedione induces the greatest absorption minimum at 420 nm. After inducing the maximal spectral response possible with II -deoxycorticosterone, subsequent addition of androstenedione results in a deepening of the absorption minimum at 420 nm. This suggests that androstenedione, which serves as a substrate for II β-hydroxylation, responds with both mitochondrial and microsomal cytochrome P-450 moieties in these preparations. The former seems likely associated with the II β-hydroxylation reaction, the latter remains unexplained. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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